Telephone-exchange system.



A..E. LUNDELL. TLPHONE EXCHANGE SYSTEM.

APPLICATION FILED lune n. 1916.

Lmfm, www@ Jan. 29,1918..

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A. E. LUNDELL.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 17| 1916. l

Lg (mgm l A Patented Jan. 29,19%.v

. 2 SHEETS-SHEET 2 III ALBEN E; LUNDELL, OF YORQVN. Y ASSIGNOR T0VVESTERNVELECTRIC COMPANY,

moonronarnn, or New vorn,

N. Y., A GORPORATlON 0F NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.`

Patented Jan. 29,191@

` p Application filed June 17, 1916. Serial No. 104,232.

T0 all whom t may concern.'

Be it known that 1, ALBEN E. LUNDELL, a citizen of the United States,residing at New York, in the county of Bronx and State of New York, haveinvented certain new and useful Improvements in Telephone- ExchangeSystems, of which .the following isa full, clear, concise, and exactdescription. y V

This invention relates to telephone eX- change systems,and moreparticularly to telephone exchanges in which the establishmeut ofconnections is controlled from an operators position.

Intclephoue exchange systems in which there are provided a plurality oiconnecting or cord circuits at an operators position to which anoperators telephone set is common, a plurality of. switching devices areprovided for controlling the association of the operators telephone setwith the connecting circuits. 1n such systems it may happen that theoperator, after having actuated one vof the switching devices. forconnecting her telephone to a connecting cir# cuit, fails to release theswitchingdevice, and therefore, when another switching device isactuated for connecting the telephone set to another connecting circuit,the operator will be connected to two connectingcircuits, and may eXtendthe connecting circuit to which one party is connected to a line desiredby the other party. i

In order to prevent the occurrence of such undesired connections, it hasbeen proposed to move one of the switching devices out of a listening-inposition, while another switch ing device is moving from the normal tothe listening-in position. For the purpose of insuring the properfunctioning of the Vsystem, a time intervalk has been provided be tweenthe normal and the listening-in posi tions of the switches. Thedisadvantage oi such arrangements is that the building up of connectionsis slowed down, and further, that due to inaccuracies in the adjustmentol magnets or mechanisms, the proposed time interval will not provesufficient.

V1t is the object of this invention to provide means for definitelycontrolling the cooperation of a plurality of switching devices such assequence switches employed for the above delined purpose, whereby theoccurrence of double connections is prevented without the necessity ofinterposing time margins between the normal and listening in positionsof the switches. Preferably a, switch is moved out of its listening-inposition while another switch is in a resting position and will, in'`turn, move this later mentioned switch into the listening-in position.

In the drawings Figure 1 represents a calling and called subscriberscircuit and an operators connecting circuit and apparatus; and Fig. 2 anoperators controlling apparatus. Only so much is shown of the circuitsand apparatus as is necessary for a clear un derstanding of thisinvention. A i'ull disclosure of a system of the same general type maybe had from Patent No. 1,168,319, patented January 1S, 1916, to A. E.Lundell.

A calling subscriber at substation 1, desiring to' obtain a connectionwith a called subscriber at substation 2, removes his rcceiver from theswitchhook, causing thereby the displaying of a well-known calling linesignal. The operator inserts then her plug Y 3 into jack 4, closing thusa circuit from grounded battery through a resistance 5, the sleevecontacts of jack t and plug 3, and the winding of arelay 6, to ground.Relay 6 closes a circuit from ground through its armature and frontcontact, a Contact 7 and the power magnet of a sequence switch 8, togrounded battery, and this sequence switch is moved out of its normalposition 1 and under the control oi' a normal spring 9 into a restingposition 2.

Sequence switch S controls the connection between the operatorstelephone set 10 and a connecting circuit 11. Another sequence switch 12controls the association of the op erators telephone head set 10 withanother connecting circuit (not shown). Supposing that the sequenceswitch 12 is in the listen-y ing-in position t, and therefore a circuitis closed from ground through contact 13 of sequence switch 12,conductor 14, and the winding of a relay 15 common to the cord circuitsof the operators position, to grounded battery. Relay 15 beingenergized, sequence switch 8 remains in position 2. A circuit is closednew from ground through contact 1G of sequence switch 8, conductor 17, acontactlS and the power magnet of sequence switch 12, to `groundedbattery, and under the control oi a normal spring 19, this sequenceswitch is moved out of position 4t into a listening-out position 11.

When sequence switch12 leaves position 511,-, the circuit oit the commonrelay 15 is Y grounded battery,

opened, this relay becomes denergized and closes Va circuit from groundthrough its armature and'back contact, a contact 20 and the power magnetof sequence switch S, vto

for moving` this seolnence switch vinto the listening-in position -l,Vin which position the operators telephone l is connected throughsequence switch contacts 2l and 22, to the connecting circuit l1 andthus into telephonie association with the calling-subscriber. Y

rThe operator haring learned the number ot' the desired line, actnatesher keyboard Vtnotshown) in accordance with the numerical designation otthis line, for adjustingv a sender adapted to control a train Aotautonnitic selector switches such as '26, QT

and 28. Y'

Then-sequence switch S reached position 4f, a circuit was closed-itromground` through the armature and front. contact of relay G, sequenceswitch contact 30, the contact 31 and the power magnet ot sequenceswitch 32 to grounded battery. Under the control ot' a normal spring Q3,sequence switch 32 is/inoved out of position l into position l1.

Then sequence switch passes through position 2, a circuit is closed fromground through sequence switch contact 33,'con! ductor 34, a wiper 35 ofa well-known cord tinder 3G adapted to connectthe operators controllingapparatus with the selected con- Ynecting circuit, a contact 3T ofsequence switch si@ and the winding ot' a relay 39 to grounded battery.VThis relay becomes energized, and, by attracting its vright-handarmature, closes a driving circuit tor a se'- qnence switch 4;() througha'sequence switch contact 4l, for moving this sequence switch out ofposition l into position Relay 39 does not become denergized whensequence switch 4:0 leaves its first position, a circuit being closedtroni grounded battery through the winding ot this relay, sequenceswitch contact tithe lett-hand contact and armature otrelay 39, cordfinder brush t3, conductor dit and contact 5 ot sequence switch 32 to`ground.

The operator dcpresses now 'her start key lf3, whereupon a circuit isclosed troni ground` through the Contact ot key 46, and a contactLl'T'and the power magnet of'seduence switch Ll() vtogrounded battery,for moving this switch out ot' position into position y8. A circuit isthen closed from ground thronghsequence switch contact 50, a contact 5land the power n'iagnet of sequence switch-38fto grounded battery, andthis switch is moved out of position l into position 2.

In position 2 of/'sequence switch 38 and position ll of sequence switch32, the funda- Y mental or controlling circuit is extended to selectorswitch 26, this circuit being trace- `able through sequence switchcontact 55,

conductor 5G, cord linder brush 5T, the windings of a stepping relay 5S,the lett-hand contact and armature ot a relay 59, sequence switchcontact G0, cord Iinder brush Gl, con ductor (32 and sequence switchcontact (33. Under the control ol reverti ve impulses sent from selectorQG to the stepping relay 5S, the sender is caused in the well-knownmanner to be stepped toward its normal position. After the setting` otselector switch 2o in accordance with the lirst digit designated bysender 25, relay becomes energized in the well-known manner and opens atits lett-hand contact the fundamental circuit. causing thereby tl iarresting ot selector 2o on the selected row of terminals, whereuponswitch 2G automatically hunts tor a tree trunk in. the selected group.Relay closes also a driving circuit trom ground. through its right-handarmature and contact, a contact Git and the power magnet ot sequenceswitch 38 to grounded battery 'tor moving this switch out of position 2into position -i-. whereupon relay 5S) again becomes deiinergized andreestablishes the tuxulamental circuit, .which is now extended throughthe wipers ot' selector 2G to a trunk leading (o another selector 2T.Selector' 2T and counector 28 are controlled in their setting operationin the same manner as was described in connection with selector 2G. withthe exception that connector 28 is adjusted in accordance with twodigits for selecting the line leading to substation Q. A\.t`ter thesending out ot each digit, relay 5) is energized and closes the abovetraced driving circuit for sequence switch 38, wherebyf a'lter thesetting ot connector 28, sequence switch HH is moved out of position 8into position Sl. A circuit is then closed from ground through sequenceswitch contact (35. cord tindcr brush 66, conductor 6T, a contact GS andthe power magnet of sequence switch 32 to -grounded battery, and thisswitch is moved ont ot position l1 into position lo. ln position 1G ofsequence switch 38, the talking circuit is established through sequenceswitch contacts and 7l, the called subst ation being signaled in anywell-known manner.

Then sequence switch 3Qy leaves its position ll, contact 45 is openedand therefore relay 39 becomes deinergized and closes a circuit tromground through its right-hand armature and back contact, a contact 72and the power magnet of sequence switch t0 to grounded battery, 'tormoving the sequence switch ont of position S into position 17, A

circuit is now closed trom ground through the right-hand arniature andback (ontact ot relay 39, sequence switch contact 73. conductor 74S, a.contact 75 and the power mag net of sequence switch 3S to groundedhaltery. whereupon sequence switch 55S is driven out of position 9 intoits first position.

, When sequence switch 38 reaches position l,

lll() .lltl

apparatus being released to normal, it may.

be employed now for controlling the establishment oit anotherconnection.,

After the operator has finished the conversation with the callingsubstation, she

' depresses a listening-out key 100, whereupon a circuit is closed fromground through the contact oi' this key 100, a contact 101 and the powermagnet of sequence switch 8, to grounded battery, and this sequenceswitch is moved into a listening-out position 11, in which position theoperators telephone set 10 disconnected from the connecting circuit. Ijtttor any reason the operator desires to listen in again, she depresses alisteningin ltcy 102, closing thus a circuit from ground through thecontact of this key, a contact 100 and the power magnet of sequenceswitch 8 to grounded battery, for moving this sequence switch intoposition 1, and relay 6 being energized, a circuit is closed throughsequence switch contact 7 for sequence switch 8, for moving this switchinto position 2. Due to the denergized condition of relay 15, thesequence switch moves into position 4.

-`'"Vhen the parties have finished their conversation, the operator, bypulling out plug 8 from jack 4, causes the denergization ot relay 6,which in turn closes a circuit from ground through its armature and backcontact, contact 103 and the power magnet of sequenceswitch 8 togrounded battery, causing the movement oi sequence switch k8 out ofposition 11 into position 1. l/Vhen sequence switch 8 reaches position1, a circuit is completed from ground through the armature and backcontact of relay 6, sequence switch contact 104, a contact 105 and theGower magnet of sequence switch 82 to grounded battery. Due to theclosure of this circuit, sequence switch 32 will be moved into position1 and the switches 26, 27 `and 28 employed in the connection arerestored to normal in the well-known manner.

Should the operator fail to depress key 100 and employ sequence switch12 for extending her telephone set to another connecting circuit, thissequence switch when moved ont of position 1 into position 2 by a relaycorresponding to relay 6, causes the closure ot a circuit from groundthrough a contact 106, conductor 17. a contact 107 and the power magnetof sequence switch` 8 to grounded battery for moving this sequenceswitch out of position 4 into position l1,

from which position the sequence switch 8 is moved to positi-on 1 by theabove traced circuit extending from the back contact of relay G. throughcontact 103. Sequence switch 8 maintained relay 15 energized inpositions 4 to 5J, through a contact 108 which will now open the circuitof this relay, whereupon switch 12 is moved into position 4 in the samemanner as above described in connection with sequence switch 8.

l/Vhat is claimed is:

1. Ina telephone exchange system, a plurality of lines, a plurality ofconnecting circuits by means of which said lines may be interconnected,an operators telephone set, a switch for each of said connectingcircuits adapted to associate said telephone set therewith, and meanscontrolled by one switch while at rest for actuating another switch.

2. In atelephone exchange system, a plurality of lines, a plurality ofconnecting circuits by means of which said lines may be interconnected,an operators telephone set, a switch for each connecting circuit adaptedto associate said telephone set therewith and having a normal, a restingand a listening-in position, means operative upon the extension ot aconnecting circuit to a calling line for moving the associated switch toits resting position, means controlled by said switch in its restingposition for moving another Y switch which is in the listening-inposition,

and means controlled by said later mentioned switch for moving the irstmentioned switch into the listening-in position.

8. ln a telephone exchange system, a plurality of lines, a plurality ofconnecting circuits by means of which said lines may be interconnected,an operators telephone set, a switch for each of said connectingcircuits for associating said telephone set therewith and having aresting and a listening-in position, and means controlled by any one ofsaid switches when moved into the resting position for actuatinglanother switch which is in the listening-in position.

4. In a telephone exchange system, a plurality of lines, a plurality oiconnecting circuits for said lines, an operators telephone set, a switchfor each of said circuits for connecting said telephone set thereto andhaving a resting' and a listening-in position, a relay, means foractuating said relay when any oi said switches is in the listening-inposi- @epilee of this patent may be obtained for five cents each, byaddressing the Commissioner oi Patents,

- Washington, D. C.

